Programmer for fluid analysis



Nov. 15, 1966 H. HELLER ETAL 3,285,054

PROGRAMMER FOR FLUID ANALYSIS Original Filed May 24, 1961 4 Sheets-Sheet1 4O 20 PROGRAMMER 46 if 26/ VALVE 125cc: 0L2 3O PuLsEo RELAY osmouakSYNC. 43, 2 20m DC PULSEPYNCZOF 0 ice Lmrr IZATION A LS SIGNAL Lac? WITCHES 34 58- SIGNAL ATTENUATION NETWORK FINE ZERO S52v0 llzvzzsms M0102aa- I [m n 512 PPING RELAY REGULATED 56 INDICATOR 44 Powu Surm' P iq.1.

INVENTORS. HERBERT HELL E2 HENRY .1. TH 1v cz rrow .1. sassnzr a1.xnzvasz c. MSI/VNES BY 19124 (7. 550x52 Nov. 15, 1966 H. HELLER ETAL3,285,054

PROGRAMMER FOR FLUID ANALYSIS Original Filed May 24. 1961 4 Sheets-Sheet2 ":ESID. use

NOV. 1966 H. HELLER ETAL PROGRAMMER FOR FLUID ANALYSIS Original FiledMay 24, 1961 4 Sheets-Sheet 5 IIOAC Nov. 15, 1966 H. HELLER ETALPROGRAMMER FOR FLUID ANALYSIS 4 Sheets-Sheet 4,

QTTaJEZA/ED" United States Patent 3,285,054 PROGRAMMER FOR FLUIDANALYSIS Herbert Heller and Henry J. Then, Pittsburgh, Clayton J.Bossart, Monroeville, Alexander C. Mclnnes, Export, and Earl M. Becker,Pittsburgh, Pa, assignors to Mine Safety Appliances Company, Pittsburgh,Pa., a corporation of Pennsylvania Original application May 24, 1961,Ser. No. 112,446, now Patent No. 3,199,338, dated Aug. 10, 1965. Dividedand this application Dec. 24, 1964, Ser. No. 420,910 3 Claims. (Cl.7323.1)

This application is a division of application Serial No. 112,446 filedMay 24, 1961 for Fluid Analysis, and now Patent No. 3,199,338.

This invention pertains to fluid analysis and particularly to the meansfor analyzing gases using gas chromatography principles.

The invention pertains to fluid chromatography either the adsorptiontype or the gas-liquid partition type. Merely for the purposes ofillustration, this invention will be described in connection withadsorption chromatography wherein acolumn or columns contain appropriateadsorbents, usually in granular form, to separate various constituentsof a gas sample or samples. The sample is introduced to the column in acarrier gas stream continuously flowing through the column. Variouscomponents of the gas sample are separated by the process of selectiveadsorption and desorption so that the separated constituents issue fromthe end of the column in sequential order corresponding to theirvolatility, weight or property affecting the degree of adsorption on thepacking material in the column. conventionally, the separated gasesemerge from the column and then pass through a suitable detector elementwhich in some known way measures the property of the gas indicative ofthe character and amount present.

Prior art devices have not been fully satisfactory in that theinstrument which programs or times the sequence of events lacksprecision and flexibility. These devices, also, require improvement inthe valving and valve control used in the chromatographic columns. Inaddition, experience has shown that previous analyzers were notaltogether stable because of uneven temperature conditions. Moreover,such analyzers are restricted in column arrangement and operation.

It is an object of this invention to overcome the aforesaiddisadvantages by providing an analyzer which is precise and flexible inits operations, stable insofar as internal and ambient temperatures areconcerned, and permits the use of at least two columns to be operatedindependently or simultaneously in either direction with the option ofusing the two columns in series or parallel.

The invention will be clearly understood with reference to the followingdescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 shows a schematic and diagrammatic wiring circuit of thisinvention;

FIG. 2 is a schematic diagram showing the pulsed relay andsynchronization circuit of FIG. 1;

FIG. 3 shows the programmer schematically;

FIG. 4 is a fragmentary view of the tape used programmer;

FIG. 5 is a perspective view, partially exploded, of the chromatographicvalves and the valve controller;

FIG. 6 is a schematic flow diagram of the analysis unit;

FIG. 7 is a schematic wiring diagram for the valve controller of FIG. 5;

FIG. 8 is a vertical sectional housing; and

FIGS. 9 and 10 show the high and low temperature control circuits,

in the view of the analyzer "ice Referring briefly to FIG. 1, aprogrammer 20 sets up a program of gas analysis for the chromatographhaving therein a detector 24 and valve positioner 28. The signal orpulse produced by programmer 20 is fed into a pulsed relay 30 andsynchronization circuit 31, the output D.C. pulse of which is fed intothe DC. stepping relay 34. This relay is a four level, four interruptercontact type with 26 steps (the contacts and some of the steps are notshown). Relay 34 serves indicator 36 which enunciates the functions ofthe levels of relay 34, valve positioner 28, synchronization circuit 31,signal attenuation network 38, recorder 40 and fine zero servo 42. Eachsignal produced by the pulsed relay 30 causes the four levels of relay34 to advance one step. The synchronization pulse initiated by theprogrammer 20 as a results of portion 27 (FIG. 4) is sensed bysynchronization circuit 31 to cause the relay 34 to return to its numberone contacts by way of synchronizing signal fed to level 34A. The longpulse produced by the wide portion 27 is sensed by a time delay relay31A (FIG. 2) which feeds the synchronizing signal to relay 34 to resetall relay levels. If, however, all levels are at their number onecontacts, the synchronizing pulse has no aflect on relay 34. Level 34Bproduces a chart drive signal received by recorder 40. Simultaneously,level 34C pr0- duces a signal to indicator 36 and valve positioner 28,and level 34D produces three signals; one to actuate valve positioner28, one received by signal attentuation network 38 to accomplish theproper attenuation and one which feeds servo 42 for adjusting the finezero of detector 24. This fine zero can be manually adjusted by knob 45.Regulated power supply 44 supplies power to detector 24. Push button 46permits the system to be operated manually if the programmer 20 is notused. All of these components coact to manipulate the chromatograph in apredetermined fashion to effect gas analysis.

FIG. 3 shows the programmer or sequence timer 20 comprising a tape orfilm 21, such as, a 16 millimeter film. This tape is threaded aroundsmooth spools 23 and a sprocket 23A in a continuous loop. One of thespools 23 rides in a slot 25 for adjusting the tightness of the tapearound the spools. As is best seen in FIG. 4, tape 21 contains sprocketholes 26 for engagement with sprocket 23A. Numeral 27 represents a wideblanked or darkened portion which interrupts the light radiated by lamp29 to cause a synchronization D.C. pulse to register in photoelectricreceiver 29A to close relay 30B. Numeral 32 referse to marks placed onthe tape to produce pulses as just mentioned. These marks are placed atselected intervals by pencil or any other suitable marking means so thata preset programming is available for the chromatograph. Time divisionmarks 33 act as guides for marking the tape.

The basis for sequence timing is the passing of tape 21 between thephotoelectric transmitter and receiver at a sequence speed. Each mark onthe film will cause the receiver to feed a signal to pulsed relay 30 andsynchronization circuit 31 which in turn advances the stepping relay 34.The tape is graduated on a time basis, one second divisions, forexample, and the length is cut to correspond to the analysis time or amultiple of the analysis time required. As the stepping relay contactsdo not advance until the end of the marking, the thickness of the markis of no consequence and the timing is determined by the placement ofthe trailing edge of the mark. Portion 27 provides a long pulse that issensed by relay 31A of circuit 31 (see FIG. 2) to reset the steppingrelay 34. As this relay should be at its first step at this time of thecycle, portion 27 will monitor synchronization. The system will beaccurate to the extent of automatically synchronizing within one filmloop during start-up or after a momentary power failure. The light beamintensity of lamp 29 is adjusted to provide proper sensitivity.

FIG. 2 schematically shows specific details of the pulsed relay andsynchronization circuit. When, for example, a programmed mark 32 passesbetween light source 29 and receiver 29A, the resistance of 29A isincreased thereby increasing the voltage on the grid of gaseous tube30A. Increased grid voltage causes the tube to conduct current toenergize relay coil 30B closing normally open relay contacts 30C and 30Dto permit DC. voltage to energize coil '34T of stepping relay 34 throughconductor 130. Energizing coil 34T opens normally closed switch 34V andmechanically prepares the sliding contacts of levels 34A, 34B, 34C and34D for subsequent sliding advancement. When opened, switch 34Vinterrupts the power supply through conductor 138 to relay 34 to preventarcing when the contacts of the levels advance. The mark having beenpassed, the tube and relay revert to original operating conditions, andDC. voltage is removed from coil 34T. It is characteristic of relay 34that, when coil 34T is deenergized, levels 34A, 34B, 34C and 34D eachadvances one step in its sequence with the same step number for eachlevel. It will be noted that the closing of contacts 30C and 30Dconducts current to heater 31D of thermal relay 31A. Since, however,mark 32 is not wide enough, coil 30B is deenergized before normally open'bimetal switch 31B is closed.

When an abnormally long precalibrated mark, such as mark 27 (FIG. 4),passes between the source 29 and receiver 29A, the operation is the sameas described above except that coil 30B is energized for a much longerperiod of time. This long energization permits heater 31D to closebimetal switch 31B and pass current to coil 34T through conductor 134.When the mark 27 passes, coils 30B and 34T will be deenergized and relay34 will ad- Vance one step. Should this step be other than step one oflevel 34A, voltage will be transferred through conductor 138, switch34V, the sliding contact of level 34A, conductor 136, closed switch 31Band conductor 134 to energize coil 34T. At this time, coil 34T will openswitch 34V thus becoming self-interrupted. This interruption willadvance relay 34 one step. The process is repeated until step one of 34Ais reached. Since step one does not provide a closed circuit, it isnecessary to energize coil 30B by another mark to actuate relay 34. a

The effect of a program marking may be simulated by closing push-button46. When switch 46 is depressed, resistance 46A is placed in parallelwith resistance 30E. The parallel resistance of this combination islowered so that the voltage across 29A and the grid of tube 30A isincreased enough to actuate the tube and relay 30B as previouslydescribed.

Thusly, it is seen that the programming by programmer 20 is extremelyaccurate, flexible and easily adapted to provide any combination ofanalysis time and sequence as required.

Looking now at FIG. 5, valve positioner 28 comprises a conventionalreversible motor 50 which drives cam 51 and driver 53 through gear-box52 and shaft 54. Driver 53 drives cam follower 55 which actuatessprockets 56 and 57. The sprockets and driver are commonly known as ageneva movement indicated by numeral 60. Briefly, when follower 55rotates counterclockwise through 180, it engages sprocket or cam slot56A to effect 90 clockwise rotation of sprocket 56. Similarly, 180clockwise rotation of follower 55 engages slot 56A to take it back toits original position through a 90 rotation; Follower 55 engages slot57A in the same manner. Although sprockets 56 and 57 each have four camslots, only one of each is numbered. Sprockets 56 and 57 actuate valves61 and 62 which provide the required fluid flow in the chromatographiccolumns 65 and 66 schematically shown in FIG. 6. Cam 51 (FIGS. and 7)actuates switches 70A, 70B, 70C and 70D. Switches 70A and 70C throughconductors 72 and 73 determine the direction in which the motor 50 willrotate depending upon which motor winding is powered through the motorrelay circuit 50A between motor 50 and levels 34D and 34C of relay 34.Power on conductor 72 drives motor 50 counterclockwise in step one oflevel 34D and clockwise in step three. Power on conductor 73 drivesmotor 50 clockwise in step two and counterclockwise in step four.Switches 70B and 70D provide a means for synchronizing the position ofvalves 61 and 62.

Referring to FIG. 7, the arrows V, W, X and Y indicate direction andextent of cam rotation. When the motion of cam 51 is in the direction ofarrovs V, motor 50 turns in a counterclockwise direction. Similarly,when the cam moves in the direction of arrows W, X or Y, motor 50rotates in clockwise, or counterclockwise direction, respectively.Switches 70A and 70C are normally biased closed and are opened by lobe51A. Switches 703 and 70D are normally biased open and are closed bylobe 51A. To actuate cam 51 in the direction of arrow V, step one onlevel 34D of relay 34 powers conductor 72 through switch 70C. Thiscircuit to motor 50 is completed through contact 154 of relay closedupon contact 156 and motor conductor 157 to rotate the motor in acounterclockwise direction. This motion is completed when lobe 51A opensswitch 70C. During this rotation of cam 51, latching relay 74 isenergized by Way of switch 70D when lobe 51A closes it to close contacts75 and 77. To actuate cam 51 in the direction of arrow W, step two onlevel 34D powers conductor 73 through contacts 75, 77 andswitch 70Awhich is now closed. This circuit to motor 50 is completed throughcontact 151 of relay 150 closed upon contact 152 and motor conductor 158to rotate the motor in a clockwise direction. This motion is completedwhen lobe 51A opens switch 70A. The direction noted by arrow X isaccomplished .by step three of level 34D supplying power to conductor 72through switch 70C. Simultaneously with the movement of the slidingcontact of level 34D to step three, the sliding contact of level 340also is at its step three energizing relay 150 to close contacts 151upon 153 and 154 upon 155. Thus, conductor 72 is connected to motor 50through closed contacts 154, 155 and conductor 158 to rotate the motorclockwise. During this rotation of cam 51, latching relay 74 by way of70B closes contacts 75 and 76. Similarly, the direction indicated byarrow Y is accomplished by position four of level 34D supplying power toconductor 73 through contacts 75, 76 and switch 70A. Since step four oflevel 34C is still holding relay 150, conductor 73 is connected to.motor 50 through contacts 151, 153 and conductor 157 to rotate themotor counterclockwise. These last two motions are completed in the samemanner mentioned above for the first two. The change in direction ofmotor 50 ositions valves 61 and 62. Directions V and W permit valve 61to be driven first in a clockwise direction and then in acounterclockwise direction. Directions X and Y permit valve 62 to bedriven first in a counterclockwise direction and then in a clockwisedirection. It is to be noted that cam 51, and valves 61 and 62 arecorrelated in a manner whereby, if directions of the cam areunintentionally missed for one reason or another, the valves will beplaced in their original positions at the start of every sequence. Forexample, after step one of level 34D has etfected the first movement ofvalve 61, the only signal that could cause motor 50 to rotate is oneresulting from step two. Steps one and three would be inoperative sinceswitch 700 would be open and step four would be inoperative because ofopened contacts 75 and 76. Nhen step two has effected movementcompletion of valve 61, the only signals that are operational are thoseresulting from steps one and three. Step four will not cause operationdue to open contacts 75 and 76. The other phases of valve rotation aresimilarly governed. Thus, valves 61 and 62 will always operate in theproper sequence.

One example of a typical flow scheme can best be seen by referring toFIG. 6. The initial position of valve 61 is represented by the dottedline position and. the initial position of valve 62 is represented bythe solid line position. Carrier fluid, for example, helium, entersinlet 81, through ports A and F of valve 61, thence to column 65, toports M, N, I and J of valve 62, to column 66, to ports K and L (valve62) and finally to outlet 81A and detector cell 24. This detector cell,as an example, is a conventional thermal conductivity cell. Sample gas,for example, hydrocarbons such as methane, ethane and propane, entersinlet 83 and passes through ports G, C, B, E, D and H of valve 61 tooutlet 83A. The initial Step of the cycle is the actuation of valve 61to the solid line position by rotation in the V direction and extent.Sample gas is now diverted through sample inlet 83, ports G and H tooutlet 83A. Helium enters inlet 81, ports A, B, C, D, E and F to column65, thus sweeping a known volume of sample gas from sample conduit BCDEinto column 65. Valve 62, in the meantime, remains in the solid lineposition, so that columns 65 and 66 are in a series flow path. After asuitable time period, long enough to insure complete flushing of thesample conduit, BSDE, valve 61 is returned to the dotted line positionby rotation in the W direction and extent, resuming sample gas flow frominlet 83 through ports G, C, B, E, D and H to outlet 83A. Helium flow isnow direct from inlet 81, through ports A and F to column 65. When thelight components in the sample gas have entered column 66, but notexited therefrom, valve 62 may be actuated to the dotted line positionby rotation in the X direction and extent, trapping column 66, betweenports I and K of valve 62, in a non-flow condition. The heavy componentseluting from column 65 may then pass through ports M-and O, a suitablerestrictor, ports P, N, I and L to out-let 81A to detector 24, thusbypassing column 66.

When the heavy components have been eluted through detector 24, valve 62may be actuated to the solid line position by rotation in the Ydirection and extent, resuming series flow of helium through columns 65and 66. The light components of the sample are now eluted from column 66through ports K and L, outlet 81A, and detector 24. Valves 61 and 62 arein position to begin a new analytical cycle. Many combinations of valveactuation may be accomplished by modifications of the sprocket drivemechanism and stepping relay circuitry for applicability to other fiowschemes.

The analysis unit or chromatograph is housed in a Crouse-Hinds type EPCexplosionproof condulet or housing 85 as shown in FIG. 8. This type ofstructure facilitates both maintenance and thermosta-ting of theassembly. Housing 85 comprises an outer metallic cylinder 78 andintermediate metallic cylinder 80 having an upper opening 82 and loweropening 83. Inner metallic cylinder 86 is of the Dewar flask type havinga bottom member 88 forming chamber 87. Mandrel 90 is fabricated from aheavy aluminum mass and is shaped as a truncated cone. Chromatographiccolumns 65 and 66 of metallic tube are wrapped around mandrel 90, andare connected to valves 61, 62 and detector 24. The fluids enter thevalves and into columns 65 and 66 to pass into detector cell 24, andthen are vented. The columns, valves, detector cell and gas conduit aremerely shown schematically for ease of illustration. A mandrel heater 92is imbedded in the mandrel 90 for purposes explained later. A thermistor94 is located at opening 82, and bimetal thermostats 95 and 96 arelocated in the mandrel. Motor driven fan 98 is located at the bottom ofcylinder 78, and an electric heater 99 is positioned around the lowerend of cylinder 80.

Two temperature zones are set up by the abovedescribed structure.Chamber 87 constitutes the high temperature zone. This zone contains theadsorption columns, valves, geneva movement, and the thermalconductivity detector cell. A 3000 watt heater 92 is employed as asource of heat. Noting FIGS. 8 and 9, the operation is explained when afast warmup of the apparatus is desired. Depressing push button 103applies 110 v. A.C. directly to heater 92 through conductors 101, switch104 and conductor 105. Switch 104 is closed by the actuation of relay106. Relay 118 opens switch 107 and closes contact 109 with 110. Thisheat is applied until the temperature level of bimetal low temperaturethermostat is reached. This temperature is several degrees below theoperating temperature selected for the chromatographic columns. Duringthis time, safety thermostat 96 is closed and relay 113 has closedswitches 114 and 116.

When the above mentioned temperature level has been reached to openthermostat 95, and since safety high temperature thermostat 96 isclosed, relay 118 closes switch 107 and opens contacts 109 and toprovide power through a 32 volt step-down transformer 117. If thetemperature exceeds 500 F., for example, thermostat 96 will open cuttingoff all power to heater 92.

The low temperature zone is located in the space designated as 120 (FIG.8). This zone must be under thermal control to provide constant heatflow from chamber or zone 87. As long as heat flow is constant,temperatures can be made stable by even supply of heat to match the flowfrom the chamber. Air is directed through the low temperature zone 120by means of a motor driven fan 98. This air is warmed when required by a450 watt heater 99 which is governed by a balanced thermistor bridgecontrol unit 122. A glass encased thermistor sensing element 94 formsone side of the bridge and senses temperature changes as small as 03 F.As thermal equilibrium exists between the high and low temperature zone,the temperature at this point should not vary very much, but as theambient temperature varies, the thermistor will sense this change toheat up the low temperature zone to maintain a stable temperature withinthe high temperaturezone. Indicating light 124 is merely a visual meansto determine whether the heater is operating. Thusly, it is readily seenthat stable temperature is provided throughout the main portion of theanalyzer so as to insure sensitivity and stableness in the analyzer.

Detector 24 (FIGS. 1 and 8) quantitatively detects the gases separatedduring passage through columns 65 and 66. The gases leaving outlet 81Aof column 66 are passed through a thermal conductivity cell in detector24 producing signals characteristic of the gases. These signals arepassed through signal attenuation network 38 to recorder 40 whichindicates, the amount and. kind of gases. If the signals are of suchmagnitude as not to be compatible with the scale of recorder 40, network38 will attenuate the signals to properly record them. The mag ni-tudeof these signals are predetermined by calibration with known samples ofgases so that the proper network 38 can be selected to match the typerecorder 40 desired. The detector signals are attenuated at programmed.intervals determined by the number of relay steps selected on level 34Dof relay 34. Thus, the manner of marking programmer 20 determines thesequence of signal attenuation relative to the sequence of operation ofall other analyzer components.

A brief description of the manner in which the analyzer operates willnow be stated. After the housing 75 has been properly preparedtemperature-wise and tape 21 marked to provide the desired programming,the gases to be measured. are connected to the inlet of valve 61. Tape21 is started and the marks thereon produce signals responded to bypulsed relay 30 and synchronization circuit 31 to actuate the fourlevels of stepping relay 34. Level 34A further forms a loop with circuit31 for resetting all levels of the relay to the starting position when alonger signal than normal is produced by the programmer. As the levelsoperate in sequence, valves 61 and 62 are rotated in the predeterminedsequence by geneva movement 60 driven by reversible motor 50. Thedirection and extent in which this motor is operated is determined bycam 51 and the attendant circuits. Thus, the gases flow through columns65 and 66 in response to the rotation of valves 61 and 62. The gasesleaving column 66 flow through detector 24, the signals from which areattenuated at network 31 and indicated in recorder 40. The thermostatingof housing 85 provides a stable temperature to insure a stablesensitivity of gas measurement. Should different sequences of gasanalysis be desirable, it is necessary only to change the markings ontape 21.

Having explained the principle of the present invention and havingillustrated and described what is considered to be the best embodiment,it is to be understood that, within the scope of the appended claims,the invention may be practiced otherwise than as specificallyillustrated and described.

We claim:

1. In a device for fluid analysis having at least one chromatographiccolumn adapted to contain sample and carrier fluid, valve meansoperatively associated with said column and selectively processing thesample and carrier fluids relative to each other for the separationthereof, a programmer comprising a flexible tape having marks thereonrepresentative of a desired chromatographic program, means to move saidtape past means responsive to said marks for producing output signals,means for receiving said signals and including relay means, a steppingrelay means for sequentially actuating said valve means and including apower source, said relay means connected in series with said powersource and actuated in response to said signals to open and close saidpower source for actuating said stepping relay means, and synchonizationmeans connected to said stepping relay means for resetting it to itsstarting position in response to certain of said signals.

2. A programming apparatus comprising a first means for producing shortsignals and at least one long signal representative of a desiredprogram; a relay having a first coil and having normally open relaycontacts connected to a power source; said first means actuating saidfirst coil to open and close said relay contacts and the closed time ofsaid contacts being determined by the length of said signals; a steppingrelay having stepped contacts, a sliding contact, a normally closedswitch and a second coil in series with said relay contacts; said secondcoil being actuated by the opening and closing of said relay contacts tosequentially actuate said sliding contact against said step contactswhen deenergized and to open said switch when energized; a time delaymeans having an energy storing means connected in series with said relaycontacts and having normally open switch means actuated by said energystoring means; said switch means connected between said second coil andeach of said step contacts except the first step and provides power tosaid second coil when closed to reset the stepping relay to its firststep; and said first means closing said relay contacts in response tosaid long signal for a time to provide suflicient energy to be stored insaid energy storing means for closing said switch means.

3. The combination of claim 2 and, said energy sturing means comprises aheater and said switch means comprises a bimetal switch.

References Cited by the Examiner UNITED STATES PATENTS 2,800,539 7/1957Edminster et al. 200-46 3,023,605 3/1962 Burk 7323.1 3,026,722 3/1962Jonach 73-116 3,164,691 l/1965 Blouin 20046 FOREIGN PATENTS 814,606 6/1959 Great Britain.

RICHARD C. QUEISSER, Primary Examiner.

1. IN A DEVICE FOR FLUID ANALYSIS HAVING AT LEAST ONE CHROMATOGRAPHICCOLUMN ADAPTED TO CONTAIN SAMPLE AND CARRIER FLUID, VALVE MEANSOPERATIVELY ASSOCIATED WITH SAID COLUMN AND SELECTIVELY PROCESSING THESAMPLE AND CARRIER FLUIDS RELATIVE TO EACH OTHER FOR THE SEPARATIONTHEREOF, A PROGRAMMER COMPRISING A FLEXIBLE TAPE HAVING MARKS THEREONREPRESENTATIVE OF A DESIRED CHROMATOGRAPHIC PROGRAM, MEANS TO MOVE SAIDTAPE PAST MEANS RESPONSIVE TO SAID MARKS FOR PRODUCING OUTPUT SIGNALS,MEANS FOR RECEIVING SAID SIGNALS AND INCLUDING RELAY MEANS, A STEPPINGRELAY MEANS FOR SEQUENTIALLY ACTUATING SAID VALVE MEANS AND INCLUDNG APOWER SOURCE, SAID RELAY MEANS CONNECTED IN SERIES WITH SAID POWERSOURCE AND ACTUATED IN RESPONSE TO SAID SIGNALS TO OPEN AND CLOSE SAIDPOWER SOURCE FOR ACTUATING SAID STEPPING RELAY MEANS, AND SYNCHONIZATIONMEANS CONNECTED TO SAID STEPPING RELAY MEANS FOR RESETTING IT TO ITSSTARTING POSITION IN RESPONSE TO CERTAIN OF SAID SIGNALS.